HP 8753E manual Loss of Power Meter Calibration Data, Interpolation in Power Meter Calibration

Loss of Power Meter Calibration Data

The power meter calibration data will be lost by committing any of the following actions: Turning power off. ‘Inming off the instrument efases the power meter calibration table.

changing sweep type. If the sweep type is changed (linear, log, list, CW, power) while power meter calibration is on, the calibration data will be lost. However, calibration data is retained if you change the sweep type while power meter calibration is off.

Chaugiug frequency. Power meter calibration data will also be lost if the frequency is changed in log or list mode, but it is retained in linear sweep mode.

Pressing m. Presetting the instrument will erase power meter calibration data. If the instrument state has been saved in a register using the k-j key, you may recall the instrument state and the data will be restored. Saving the instrument state will not protect the data if the instrument is turned off.

Interpolation in Power Meter Calibration

If the frequency is changed in linear sweep, or the start/stop power is changed in power sweep, then the calibration data is interpolated for the new range.

If calibration power is changed in any of the sweep types, the values in the power setting array are increased or decreased to reflect the new power level. Some accuracy is lost when this occurs.

Power Meter Calibration Modes of Operation

cOntinuous Sample Mode (Each Sweep)

You can set the analyzer to update the correction table at each point for sweep (as in a leveling appEation), using the ~~~~~:, &tkey. In this mode, the mdyzer checks the

power level at every frequency point each time it sweeps You can also have more than one

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sample/correction iteration at each frequency point. (See the ~~~~~:~~~~~~ softkey description in Chapter 9.)

While using the continuous sample mode, the power meter must remain connected as shown in Figure 6-55. A power splitter or directional coupler samples the actual power going to the test device and is measured by the power meter. The power meter measurement provides the information necessary to update the correction table via HP-IB.

Continuous correction slows the sweep speed considerably, especially when low power levels are being measured by the power meter. It may take up to 10 seconds per point if the power level is less than -20 dBm. For faster operation, you can use the sample-and-sweep mode. If

you use a directional coupler, youmust.../................enter.... the attenuation of the coupled arm with respect /_, .,.,:; ,.......

to the through arm using the ‘~~~~~~~~ softkey. ,.>;>;b;,.:..; ,,,..... :;>>>iii......A.....A.......A...:.......iii. s.:

Application and Operation Concepts 6-103